WA motorcyclist fatally hit by chased car

A motorcyclist has died after being hit by a car that had been involved in an on-and-off police chase for about 40 minutes in Perth.

Police first attempted to stop the car about 11.45pm on Wednesday in Seville Grove, but found it crashed into a pole on Leach Highway in Welshpool about 12.25am on Thursday.

They say the alleged driver, a 35-year-old woman, ran into bushland but was arrested after a short foot chase and is now under police guard in hospital with injuries that are not believed to be serious.

Police say the woman hit the man, who was aged in his 20s, just before she crashed into the pole.

Officers provided emergency first aid to him and he was taken to hospital but later died.

Internal affairs are investigating the circumstances surrounding the crash, including whether the car was being pursued at the time of the collision.